A common and useful type of container is the paperboard carton having a gabled top. Examples of such cartons include the everyday milk carton. In recent years, these cartons have been used for numerous other products, including foods, beverages and detergents. These cartons are typically coated or laminated with a heat-sealable plastic, which is used by manufacturers to seal the cartons.
Typically, the contents of these cartons are dispensed by ripping open the gable top and unfolding a pourable spout. Once the carton is ripped open, it cannot be tightly resealed. To address this problem, cartons have been devised with reclosable spouts. These spouts are also referred to in the field as fitments, closures and caps. For convenience, they are referred to herein as "reclosable spouts."
A conventional spout is opened and closed by means of a removable cap, snap, hatch or the like. In the case of a capped spout, a person using the carton removes the cap to dispense the contents of the carton (typically a beverage). Because the carton has not been torn open, the contents can be tightly resealed.
Cartons having reclosable spouts are typically manufactured with automatic machinery (often referred to as "packaging machinery") which forms the carton from a flat piece (or "blank") of paperboard or other suitable material. After the carton has been partially formed (but not filled or sealed), the reclosable spout is attached. A typical spout consists of a plastic cylinder having a mounting flange at one end and a threaded, removable cap (or other conventional closure) at the other. The spout is mounted from inside the carton through a preformed hole formed in the paperboard blank so that the capped end extends outward, while the flange is flush against the interior side of the carton wall. The flange is then ultrasonically welded to the wall of the carton. Examples of these types of containers and spouts are provided by U.S. Pat. No. 4,964,562 to Gordon and U.S. Pat. No. 4,601,425 to Bachner. Examples of these types of containers and spouts are also disclosed in U.S. Pat. No. 5,484,374 to Bachner et al., which is incorporated herein by reference.
The component of packaging machinery which attaches spouts to cartons is often referred to as an "applicator." One type of applicator operates in two distinct steps. First, before the carton is filled and sealed, the applicator inserts the spout through the die cut hole. The applicator then moves the carton to a second station, where an anvil is placed inside the carton to firmly hold the spout's flange against the carton wall. An ultrasonic sealer located outside the carton then welds the flange to the carton. Alternatively, a one-step applicator system, such as shown in U.S. Pat. No. 5,484,374 to Bachner et al., can be used to simultaneously insert and weld the spout.
With respect to gable-top cartons where a plastic spout is welded to the carton surface, the current applicator art includes a sonic horn which may have an `energy ring` on the horn surface and a generally flat anvil surface (which is or may be part of a rotating `anvil housing`) against which the horn presses to weld the spout flange to the carton surface. There is also typically a spout mandrel device, onto which the spout is placed, to move the spout from the `saddle` (where the spout is positioned to be picked-up by the spout mandrel), and to position the spout within the aperture of the carton. This spout mandrel is secured to the anvil by means of a machine bolt. As the anvil component is the recipient of continuous pressure and vibration during the ultrasonic sealing process, the surface of the anvil can wear and produce uneven and poor welds.
In order to weld an `inside-out-spout` to the carton surface, the ultrasonic horn with the energy ring must weld through the paperboard carton from the outside surface. The energy ring substantially compresses the paperboard as part of the welding process and, in so doing, can create ply bond delamination of the paperboard fiber and cause surface tearing. This same tearing can occur on the inside of the paperboard, which is laminated or extruded with a barrier material such as foil or polyethylene. Any tearing or pin-holing of the inside barrier material will compromise the barrier properties of the carton. Also, by positioning the energy ring on the ultrasonic horn and welding through the paperboard thickness, the energy ring is positioned at its farthest distance from the bonding surfaces.
What would therefore be desirable is an ultrasonic welding device in which the energy ring is located on the anvil in close proximity to the surfaces or components to be welded in order to minimize the deleterious side-effects of ultrasonic welding with the energy ring on the ultrasonic horn. What would also be desirable is an anvil and mandrel component that can be readily removed from an anvil housing in order to facilitate rapid change out of the anvil and mandrel without replacing the entire anvil housing when spout configuration changes or when the energy ring has excessive wear.